机翼屏蔽对航空发动机噪声预测的影响分析

Influence of wing shielding on aeroengine noise prediction

随着对飞机适航噪声的要求更加严格,利用机翼屏蔽效应对航空发动机进行噪声控制已成为一项有效策略与研究方向。基于惠更斯-菲涅尔原理,利用飞机噪声性能(Aircraft Noise and Performance,ANP)数据库计算飞机起飞航迹并在其上建立噪声源,声源位置作为噪声屏蔽计算坐标输入屏蔽效应算法,应用Matlab软件进行噪声直接声场与衍射声场的建模,并通过机翼声屏障插入损失计算分析声压级屏蔽水平,把得到的结果与Heidmann风扇噪声预测模型相结合,以评估机翼屏蔽对飞行阶段发动机风扇噪声的影响。对比有/无机翼屏蔽效应的风扇前传噪声预测结果发现:随着噪声传播路径从机翼前缘至机翼后缘的移动,机翼屏蔽效应的影响呈先增大后减小的趋势,并且噪声频率越高,屏蔽效应越明显。

With the development of aircraft airworthiness noise strictness requirements,it has become an effective strategy and research direction to use wing shielding effect to control aircraft engine noise.In this paper,based on Huygens Fresnel principle,aircraft noise and performance(ANP)database is used to calculate the aircraft take-off track and establish noise sources on it.The sound source position is taken as the coordinates for noise shielding calculation coordinate to input the shielding effect algorithm.The mathematical modeling software(Matlab)is used to model the direct sound field and the diffractive sound field of noise transmission,and the sound pressure level shielded by wing is calculated and analyzed by insert loss of wing barrier.The results are combined with the Heidmann fan noise prediction model to evaluate the effect of noise shielding on fan noise.Compared with the prediction results of fan forward noise with or without wing shielding effect,it is found that the effect of wing shielding increases first and then decreases with the movement of noise propagation path from the leading edge to the trailing edge of the wing,and the higher the noise frequency,the more obvious the shielding effect is.